1. Field of the Invention
This invention relates generally to computer hardware and, more particularly, to circuit card mounting hardware.
2. Description of the Related Art
Printed circuit board (PCB) materials are typically made of inflexible laminates containing conductive layers with successive combinations of insulating layers. Conductive layers may include copper metal, or another conductive material. Conductive layers of the PCB may be used to transport electrical energy within the laminate. Insulating layers may include glass-fiber reinforced epoxy resins or other insulating materials.
The conductive circuits of the PCB may reside in a limited area of the PCB's form. The rest of the form may have the same laminate, however, with the conductive material etched away. The portion cleared of conductive material may be used for mechanical adapting and may not serve an electrical function. The PCB may be exposed to an etching bath to remove copper from a front of the PCB, creating an imbalance of conductive material within or on the PCB (e.g., high copper content on rear 20% of a PCB's volume and zero copper content on the remaining 80% of the PCB's volume). Long exposure times to the etching bath may cause poor circuit trace quality and/or PCB warping. Differences in conductive material content across the PCB may result in differences in thermal expansion coefficients of the different materials in the PCB. The differences in the thermal expansion coefficients may result in PCB warping when the PCB is reheated during electrical component-level device assembly to a PCB surface.
Many traditional PCB laminates may be composed of interwoven glass fibers held rigidly in a matrix of cured resin, usually a thermosetting epoxy, resulting in a structure that allows for extremely limited plastic deformation. As a result, mechanical features that can be created in such a material may be limited to simple cuts with all the limitations inherent to a machined feature.